In general, the memory cards used for performing electronic payments include a semiconductor component, also referred to as a "chip", placed on an intermediate element carrying electric contacts to which the component is connected by metal wires.
The assembly comprising the intermediate element and the semiconductor component constitutes an electronic module of dimensions that are small enough to require it to be integrated in a support of greater dimensions, that is easier to handle, and that is referred to as a "card body".
Nowadays, card bodies are of a format standardized by an ISO standard, being 85.6 mm long, 54 mm wide, and 0.80 mm thick.
The electronic module may be incorporated in the card by being affixed in a machined cavity if the card body is made by rolling, or by being inserted in a mold when the card body is made by molding.
Naturally, under no circumstances can the electronic module be removed from the card body once it has been integrated therein. For example, when the sum available in a phone card has been spent, then the entire card, i.e. the module and the card body, must be discarded.
In the field of mobile telephony, there also exist electronic modules which are carried by miniature cards known as "plugs" that are much smaller in size than the above-mentioned ISO cards and that are designed to be inserted in a mobile telephone.
Some such miniature cards are presented on an ISO format card to which they can be mechanically secured, e.g. by means of slideways disposed on the surface of the card.
The card proper serves only as a support for said miniature cards, which need to be separated therefrom in order to be used, and then after use they are reconnected therewith for storage and transport.
In other cases, mobile telephone miniature cards are sold integrated in releasable manner to a card body in the ISO format. To separate the miniature card, the user must break ties connecting it to the card body, with this being irreversible. The card body is then of no further use and is discarded.
It will be observed in both of the above examples that the presence of an ISO format card body serves only to compensate for the small dimensions of the miniature card by offering the user a support that is easier to handle.
It should also be observed that under no circumstances does the card body play any role when the electronic module is in use.